Nano-robots system and methods for well logging and borehole measurements

ABSTRACT

This invention relates to a nano-robots system and methods for well logging and borewell measurements. In one embodiment, a nano-robot includes a propulsion system for providing thrust in drilling mud, with extendable fins to help steer nano-robot in the drilling mud. The fins are also extendable to a further position then when used for steering, so that the nano-robot may embed itself into a formation to measure its properties, such as porosity and permeability. In an embodiment, a nano-robot includes electrodes to generate a voltage from the ions in the drilling mud, and a transceiver and antenna to provide communication with other nano-robots, and with a transponder on a drilling string so that measured data may be transmitted to surface receivers for data storage and analysis. Other embodiments are described and claimed.

TECHNICAL FIELD

This invention relates to nano-robots system and methods for well logging and borehole measurements which are useful in reducing associated operating costs.

BACKGROUND OF THE INVENTION

LWD (Logging While Drilling) and MWD (Measurement While Drilling) are well-established techniques in the energy services industry for providing various logging and measurement parameters for oil and gas wells. For example, borehole direction parameters, such as inclination and azimuth direction, are of importance, particularly in geo-steering and non-vertical drilling applications. Formation properties such as porosity, permeability, resistivity, hydrocarbon content, to name just a few, are measured to help determine whether the well might be productive. Measuring properties of fractures, where the fractures are created to increase oil flow, is also of utility in determining productivity of a well.

Tools for LWD and MWD have been developed over decades of research and development. Many of the tools for LWD and MWD are quite sophisticated and expensive to operate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now illustrated with the accompanying drawings which are intended to illustrate the construction of an embodiment of the invention. However, it is to be understood that the invention is not limited to the construction of the embodiment herein described and/or illustrated by the drawings. The principles and features of the present invention may be employed in numerous embodiments without departing from the scope of the present invention. Such equivalent and variant embodiments incorporating modifications, changes, adaptations, are intended to be within the scope of the present invention.

In the accompanying Figures:

FIG. 1 illustrates a nano-robot according to an embodiment of the present invention.

FIG. 2 illustrates a well site with a nano-robot injector according to an embodiment of the present invention.

FIG. 3 illustrates a nano-robot injector according to an embodiment of the present invention.

FIG. 4 illustrates a method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention teaches the use of nano-robots in the areas of well logging and measurement, which may be of utility in reducing operating costs associated with well logging and measurement.

FIG. 1 illustrates a robotic-type device with applications in oil and gas well technology. Such an embodiment may be referred to as a nano-robot. Although the prefix nano is usually used to denote one billionth of some unit, the term nano-robot is not meant to imply that embodiments are limited to a size not greater than one billionth of some typical unit, such as a meter. Rather, the prefix nano in nano-robot is used merely to denote that some embodiments may be relatively small.

As an example of their relative size, a nano-robot, or a number of nano-robots, may be injected into drilling mud or completion fluid (or other viscous fluid) to provide data, such as well temperature, directional parameters of a drill, and other petrophysical parameters. For such applications, an embodiment nano-robot may be designed small enough to circulate through the drilling mud to collect such data, which may be stored or transmitted. As another example, an embodiment nano-robot may be designed small enough so as to invade a formation or fracture to provide data of interest. Such possible applications are described in more detail later.

Referring to FIG. 1, within outer-shield 102 are functional units (components): controller 104; sensors 105 and 106; fins 108 and 110; motors 112, 114, 116, and 118; transceiver 120; antenna 122, electrodes 124 and 125; and power regulator circuit 126.

FIG. 1 implies that outer-shield 102 may be spherical in shape for some embodiments. As is well known, a sphere has the largest volume to surface area ratio. However, other embodiments may have an outer-shell having a geometric shape other than a sphere. For some embodiments, outer-shield 102 may comprise one or more alloys of carbon. For example, a passive diamond material may be of utility due to its high surface energy and strong hydrophobicity, as well as chemical inertness. A passive diamond has a cage-like structure created from bonding nano-carbon particles to give a much higher strength than diamond.

Controller 104 provides control and communication to some or all of the various components in a nano-robot. Controller 104 may also include memory to store or buffer data received or sent to some or all of the various components. Controller 104 may be programmable, running under software or firmware instructions. Electrodes 124 and 125 comprise planar metal strips or plates used to generate electrical power from ions in the surrounding mud or fluid. For some embodiments, electrodes 124 and 125 may be conformal with outer-shield 102. There may be a number of such electrodes placed about outer-shield 102, but for simplicity only electrodes 124 and 125 are illustrated in FIG. 1.

For some embodiments, electrical power used to generate thrust may be provided by characteristics other than a potential difference due to the ions. For example, a temperature difference, or a pressure difference, between two plates may be utilized. In some embodiments, a single plate (which may have a nonconductive interior) having two sides (faces) may be used, so that the generated electrical power for the thrust may generated as a result of a potential difference, a temperature difference, or a pressure difference between the first side of the plate and the second side of the plate.

Power regulator circuit 126 provides voltage regulation, and includes components, such as for example capacitors, for storing charge. Such stored charge may be generated when electrodes 124 and 125 are subject to an ionic imbalance, such as when the nano-robot embodiment is in a salt dome. The stored charge may be depleted when the nano-robot embodiment is not in a zone that has an ionic imbalance, or when extra power is needed for quick steering or propulsion. In addition to power generated from electrodes 124 and 125, a battery, fuel cell, or other power generating device may be employed. Some embodiments may not employ electrodes. (For ease of illustration, connections between power regulator 126 and other components are not explicitly shown so as not to clutter the illustration.)

Motors 112, 114, 116, and 118 provide thrust, either separately or in combination, to propel the nano-robot. For some embodiments, a motor may comprise a propeller. For other embodiments, a motor may pump out fluid to provide thrust, or a motor may comprise a flexible membrane to push against the mud. Outer-shield 102 is dashed about these motors to indicate that there may be an opening at the motor positions, or that outer-shield 102 may be removable at these positions to allow propellers to extend from the motors. The embodiment of FIG. 1 explicitly shows four motors, but a different number of motors may be employed in other embodiments. Some embodiments may utilize mud circulation to move.

Sequencing the thrusting action of motors 112, 114, 116, and 118 may provide some directional thrusts to steer the nano-robot. For example, synchronizing the thrusts of motors 116 and 118, but keeping motors 112 and 114 off, will help steer the nano-robot to the right (with respect to the illustration of FIG. 1). Fins 108 and 110 may also aid in steering. Fins 108 and 110 may slide out of their respective holders, 128 and 130. For some embodiments, some or all of fins 108 and 110 may extend outside of outer-shield 102 up to a fraction, e.g., 25% for some embodiments, of their length when used for steering. For example, to help steer downward, motors 114 and 116 may thrust synchronously with fins 108 and 110 extended to 25% of their length, but where motors 112 and 118 are off. For simplicity, only two fins are explicitly illustrated in FIG. 1, but in practice, more fins may be included in an embodiment.

The fins may also provide additional functions. For example, fins 108 and 110 may extend outside of outer-shield 102 to a fraction of their length, greater than for the case when used for steering, when the nano-robot is to invade a formation. Extending the fins when invading a formation may help prevent the nano-robot from re-entering the borehole. For some embodiments, the fins may extend up to 75% of their length when a nano-robot is to embed itself in a formation. Other embodiments may make use of a different fractional amount of fin extension. For such an application, the fins may help in embedding the nano-robot into small porous channels for the formation.

Sensors 105 and 106 are deployed to collect measurements, such as borehole temperature, directional parameters, borehole pressure, formation properties, thickness of hydrocarbon zone, and mud environment, to name a few examples. When the nano-robots enter the formation, other types of petrophysical parameters may be measured, such as effective porosity and permeability, and oil-water contact, to name just a couple of examples. For simplicity, only two sensors are shown, but in practice, the number of sensors may be other than two in number. Also, some or all of the sensors may be deployed on the outside of outer-shield 102, but for ease of illustration, sensors 105 and 106 are shown inside the nano-robot adjacent to outer-shield 102.

Also, a nano-robot may be used to enter a fracture. In hydraulic fracturing, additional passageways in an oil reservoir are created to facilitate the flow of oil to a producing well. For example, reservoir having oil-containing rocks with restricted pore volume an connectivity that impede the flow of oil, are sometime fractured by injecting a fluid containing sand or other proppant under pressure to create fractures in the rock through which the oil may more easily flow. For such applications, an embodiment may include injecting nano-robots with the proppants so that they may be pumped into the fracture. The nano-robots may sense and transmit data associated with the fracture; such as for example fracture conductivity, how much residue is left in the fracture, permeability, and other petrophysical parameters. In such applications, for some embodiments the nano-robots may not be retrieved, but simply left in the fracture. The number of nano-robots to be injected may be determined by an algorithm, which may depend upon the fracture length and height, and the proppant volume to be pumped.

Transceiver 120 comprises a transmitter and receiver coupled to antenna 122 so that the nano-robot may communicate with other nano-robots, as well as other communication devices, such as a transponder (transceiver) on a drill bit assembly. Antenna 122 may be a patch antenna, and may be conformal with outer-shield 102. Other embodiments may employ different antenna designs other than a patch.

FIG. 2 illustrates, in simplified form, a system including nano-robots, nano-robots injector, well and accompanying infrastructure according to an embodiment. A well is shown with surface casing 202 and intermediate casing 204, where the arrows indicate mud flow direction. Starting from mud pump 206, mud flows through stand pipe 208, mud flow line 210, swivel 212, Kelly 214, and through drill pipe 216, out of bit 218 into the well, and then upward through annulus 220 to retrieval 222. Retrieval 222 retrieves the nano-robots. For some embodiments, during retrieval, the nano-robots are expected to flow back to the surface by assistance of the drilling mud. At the mud surface, retrieval 222 may comprise a chamber placed before the shale shaker to assist in retrieving. Some embodiments may not employ retrieval 222, for example, if nano-robots were relatively inexpensive they may be considered waste product along with other debris. The mud flow then continues to shaker and mud pit 224, whereupon it is provided to mud pump 206, and the mud flow process repeats.

For the embodiment of FIG. 2, injector 226 is located after mud pump 206 with respect to the mud flow. Its function is to inject nano-robots into the mud flow. For some embodiments, it is attached at a convenient position before the goose neck on the mud flow line. Injector 226 is coupled by way of a non-returning valve, which allows one way injection of nano-robots into the mud flow (or fracturing fluid flow if hydraulic fracturing is in progress), and mitigates the return of mud flow (or fracturing fluid flow) into injector 226.

For some embodiments, transponder 228 on drill collar 230 is used to receive information from nano-robots, and to relay such information to receivers at the drilling site. Transponder 228 may also receive information from surface transmitters, and relay such information to the nano-robots. For some embodiments, transponder 228 may communicate to the surface wirelessly using a lower frequency, and a higher power, than that available to nano-robots. In this way, communication from devices on the surface to the nano-robots deep within a wellbore is facilitated. For some embodiments, communication between transponder 228 and the surface may be by way of an electrical cable, or fiber optic, to name a couple of examples. For the case of hydraulic fracturing, for some embodiments a transponder may be placed on the bottom of casing 202, in the vicinity of the formation, and may be cemented in place.

By providing communication between the nano-robots in a borehole and surface devices, control information may be provided to the nano-robots, such as for example the type of measurements that should be made. Also, data provided by the nano-robots may be stored in surface computers in field service vehicle 232. FIG. 2 illustrates an application of nano-robots to vertical well drilling. However, nano-robots have application to other types of well drilling, such as for example non-vertical drilling involving coiled tubing.

FIG. 3 illustrates an injector according to an embodiment. Operation of injector 226 is controlled by microprocessor 302. To simplify the drawing, communication paths between microprocessor 302 and the various components in injector 226 are not explicitly indicated. Bus 304 provides communication to interface device 306 to allow communication with external devices. Interface device 306 may be a wireless device, or an interconnect, for example.

Robot holding cartridge 308 holds nano-robots in suspension of a suitable fluid so that they may be ready for loading. Cartridge releasing and holding 309 is a device used to facilitate the release and reloading of robot holding cartridge 308 into injector 226, and is operated by microprocessor 302. Gate controller 310, under control of microprocessor 302, operates gate 312 to allow nano-robots held in robot holding cartridge 308 to enter robot acceleration device 314. Robot acceleration device accelerates nano-robots to a velocity equal to (or sufficiently close to) the velocity of the mud flow. This helps prevent abrupt acceleration of the nano-robots.

When robot acceleration device 314 brings the nano-robots to a sufficiently high velocity, gate controller 316 causes gate 318 to open so that the nano-robots may exit robot acceleration device 314 and enter mud flowline connector 320. Gate controller 322 causes gate 324 to open so that the nano-robots may eject injector 226.

FIG. 3 is merely one example of an embodiment injector. For other embodiments, acceleration of the nano-robots may not be performed, for example if the nano-robots are designed to withstand a sudden acceleration from rest to the velocity of the mud flow (or fracturing fluid flow).

FIG. 4 summarizes very briefly a process cycle for using nano-robots, as discussed above. Nano-robots are injected (block 402) into the mud flow, whereupon communication and control (block 404) is provided between nano-robots themselves, and between nano-robots and surface computers. This communication may include providing commands to the nano-robots, whereby some or all of the nano-robots may be commanded to invade formations, fractures, or propel themselves to the surface for retrieval. Also, data sent by nano-robots to the surface may be stored on surface computers, as discussed previously. Nano-robots are retrieved (block 406) from the mud flow, whereupon they are available for re-use.

Although the subject matter has been described in language specific to structural features and methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Accordingly, various modifications may be made to the described embodiments without departing from the scope of the invention as claimed below. 

1. Nano-robots for well logging and borehole measurement comprising: a propulsion system to provide thrust in a viscous fluid; and a set of fins, extendable to a first position to steer nano-robots in the viscous fluid, and extendable to a second position to hold the apparatus into a formation.
 2. Nano-robots according to claim 1, further comprising at least one sensor to measure formation properties, properties associated with a fracture, and pressure and temperature of the viscous fluid.
 3. Nano-robots according to claim 1, wherein the viscous fluid is drilling mud.
 4. Nano-robots according to claim 1, further comprising electrodes to generate a voltage when immersed in the viscous fluid.
 5. Nano-robots according to claim 1, further comprising: a transceiver; and an antenna coupled to the said transceiver.
 6. Nano-robots according to claim 1 further comprising a first plate and a second plate, wherein a thrust is generated as a result of any one of a potential difference, a temperature difference, and a pressure difference between the first plate and the second plate.
 7. Nano-robots according to claim 1, further comprising a plate having a first side and a second side, wherein a thrust is generated as a result of any one of a potential difference, a temperature difference, and a pressure difference between the first side of the plate and the second side of the plate.
 8. A nano-robots system comprising: drilling mud; a mud pump to pump the drilling mud; a mud flow system coupled to the mud pump to receive the drilling mud; a nano-robot; and an injector coupled to the mud flow system to inject said nano-robot into the drilling mud.
 9. A system according to claim 8, further comprising: a borehole to receive the drilling mud, the borehole having directional parameters; and said nano-robot comprising at least one sensor to measure the directional parameters.
 10. A system according to claim 8, further comprising: a formation having formation properties; and said nano-robot comprising at least one sensor to measure the formation properties.
 11. A system according to claim 10, the formation properties including porosity and permeability.
 12. A system according to claim 8, further comprising: a fracture having fracture properties; and said nano-robot comprising at least one sensor to measure the formation properties.
 13. A system according to claim 12, the fracture properties including permeability and conductivity damage due to residue.
 14. A system according to claim 8, further comprising: a drill string including a drill collar; and a transponder coupled to the drill string to provide communication with the robot.
 15. A system according to claim 8, further comprising: a well casing; and a transponder coupled to the well casing to provide communication with the robot.
 16. A system according to claim 8, further comprising: a borehole; and a formation adjacent to the borehole; said nano-robot comprising: a propulsion system to provide thrust in the drilling mud; and a set of fins, extendable to a first position to steer the apparatus in the drilling mud, and extendable to a second position to hold the apparatus into the formation.
 17. A system according to claim 16, further comprising: a drill string including a collar inside the borehole; and a transponder coupled to the drill string; said nano-the robot further comprising: an antenna; and a transceiver coupled to the antenna to communicate with the transponder.
 18. A system according to claim 16, the robot further comprising: at least one sensor to measure properties of the formation.
 19. A system according to claim 18, the properties of the formation including porosity and permeability.
 20. A method for well logging and borehole measurements comprising: injecting a nano-robot into drilling mud; directing said nano-robot into a borehole; sensing formation properties with said nano-robot; and communicating with said nano-robot to receive data on the formation properties.
 21. A method according to claim 20, further comprising: sensing borehole directional parameters with said nano-robot.
 22. A method according to claim 20, further comprising: retrieving said nano-robot from the drilling mud.
 23. A method according to claim 20, further comprising: commanding said nano-robot to extend fins so as to invade a formation.
 24. A method for well logging and borehole measurements comprising: injecting a nano-robot into a proppant or a fracture fluid; generating a fracture; sensing fracture properties with said nano-robot; and communicating with said robot to receive data on the fracture properties.
 25. A method according to claim 24, further comprising of commanding said nano-robot to extend fins so as to invade the fracture. 